Introduction 15of grass are conducted in the summer period. The annual gross return from the
sale of livestock is of the order of Australian $1 million. Grass filtration of
sewage is employed during the winter season. A description of methods of land
treatment of wastewater is given in Chapter 8. The final effluent from the Farm
is discharged into the sea at Port Phillip Bay without causing any serious
environmental impact to the marine ecosystem. The Werribee Farm treatment
complex supports an abundance of wildlife, including over 250 species of birds
and several species of fauna and flora (Bremner and Chiffings 1991).
Table 1.3 Facts about the Board of Works Farm - Werribee, Austrialia (Bremner &
Chiffings 1991)
Area 10,850 ha
Road construction 231 km
Fencing erected App. 2,024 km
Channels constructed 853 km
Drains constructed 666 km
Annual rainfall 530 mm
Annual evaporation 1350 mm
Average daily flow 470,000 m^3 /day
Sewage BOD 5 510 mg/L
Sewage SS 450 mg/L
Area used for purification of sewage
Land filtration 3,830 ha
Grass filtration 1,520 ha
Lagoon treatment 1,500 ha
Livestock
Cattle on farm 12,000
Cattle bred on farm during year 4500
Sheep on farm 25,000-70,000
BOD 5 = 5-day biochemical oxygen demand
SS = Suspended solids
The Werribee Farm occupies almost 11,000 ha of land and treats an average of
500 million litres of sewage and industrial waste daily. Under the upgrading plan,
the land and grass filtration treatment processes were phased out in 2005 and all
sewage is being treated in lagoons which cover about 1,820 ha of land. Biogas is
being collected from the first 3 covered anaerobic lagoons to generate electricity for